Method for creating defect management information in an recording medium, and apparatus and medium based on said method

ABSTRACT

This invention provides a method for creating/writing defect management information of an information recording medium and an apparatus and optical disc based on the method. In the present invention, it depends on the type of data to be reproduced whether or not defective sectors which are detected during reproduction operation are replaced with non-defective sectors. If read-out errors are detected in reproducing non-audio/video data, linear, replacement algorithm is applied to the corresponding defective sectors. On the other hand, in case of audio/video data, location information of the corresponding defective sectors is just kept without any sector replacement. Therefore, this invention enables to reproduce audio/video data in real-time regardless of the presence of defective sectors and to avoid writing data to the defective sectors when new data is overwritten to the information recording medium.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for managing defectswhich arise in an information recording medium, more particularly, to amethod for creating/writing defect management information for aninformation recording medium, and to an apparatus and, an optical discusing the method.

[0003] 2. Description of the Related Art

[0004] Optical discs have come into wide use since the advent of CD(compact disc) and the demand for optical discs is expected to growsteadily with popularization of DVD (digital versatile disc). Opticaldiscs include read only discs such as CD-ROM and DVD, write once discssuch as CD-R and DVD-R, and rewritable discs such as CD-RW and DVD-RAM.Standard formats of CD-RW and DVD-RAM have released and standardizationfor VDR (video disc recorder) is in progress.

[0005] For rewritable optical discs such as DVD-RAM, defects which arisein their recording surface should be managed to achieve high reliablewrite/reproduction operation in a manner that data is not written tosectors in which read-out errors are detected beyond a predeterminedlevel (hereinafter referred to as “defective” or “bad” sectors). Toaccomplish this, defect management is performed such that addresses ofdefective sectors are stored in a defect management table on the opticaldisc and data access to the defective sectors, write or read-out, isprohibited.

[0006] As shown in FIG. 1, the rewritable physical area of DVD-RAM has alead-in area, a data area, and a lead-out area. The data area is dividedinto contiguous 24 groups, and guard area is situated before and behindeach group. Each group is made up of a user area for recording data anda spare area which provides a storage area in place of defective portionof the user area.

[0007] The data area is also made up of a plurality of blocks, each ofwhich consists of 16 sectors. The position of each sector is specifiedby a physical address which is given uniquely to each sector. When, datais recorded, LSN (logical sector number) is assigned sequentially toevery sector except defective ones.

[0008] Defect management information, or physical addresses of defectivesectors within the data area are stored in DMA (defective managementarea), which is provided in four places, two in lead-in area and theother two in lead-out area, as shown in FIG. 1, to protect against thedefects which may arise in the four DMA themselves.

[0009] The DMA is made up of two ECC (error correction code) blocks, or32 sectors. The first ECC block consists of one sector for DDS (discdefinition structure) and 15 other sectors for PDL (primary defectlist). Sixteen sectors of the second ECC block are used for SDL(secondary defect list).

[0010] The examples of DDS, PDL, and SDL are illustrated in tables 1, 2,and 3, respectively. TABLE 1 DDS structure Size (in location byte)contents 0˜1 2 DDS identifier (0A0Ah) 2 1 Reserved (00h) 3 1 DiscCertification flag 4˜7 4 DDS/PDL 8˜9 2 The number of groups  10˜20472038 Reserved (00h)

[0011] TABLE 2 PDL structure Size (in location byte) contents 0˜1 2 PDLidentifier (0001h) 2˜3 2 The number of entries in PDL 4˜7 4 The 1^(st)bad sector address  8˜11 4 The 2^(nd) bad sector address . . . . . . . ..

[0012] TABLE 3 SDL structure Size (in location byte) Contents 0˜1 2 SDLidentifier (0002h) 2˜3 2 Reserved (00h) 4˜7 4 SDL update counter  8˜15 8Spare area full flags 16˜21 6 Reserved (00h) 22˜23 2 The number ofentries in SDL 24˜31 8 The 1^(st) bad sector address & the 1^(st)replacement sector address . . . . . . . . .

[0013] Methods for creating and managing defect management informationsuch as PDL and SDL are explained below with reference to DVD-RAM.

[0014] PDL Creation and Management (in Write Operation)

[0015] The optical disc, or DVD-RAM is tested by the manufacturer todetermine the validity of each sector. To do this, data is written toeach sector and then read out from that sector to check whether thatsector is bad or not. Sectors in which read-out errors are detectedbeyond a predetermined level are classified as defective ones at themanufacturing time and their physical addresses are stored in the PDLone after another, as shown in FIG. 1.

[0016] If a user requests to write data to the optical disc, a writecommand is sent to the optical disc drive and then the data begins to bewritten to unused sectors on the user area sequentially, as shown inFIG. 2. Each time data is written to the target sector, the physicaladdress of the target sector is compared to those of defective sectorsin the PDL. If the target sector is matched with one of defectivesectors in the PDL, the target sector is skipped and the data is writtento the next valid sector. This scheme to compensate for defectivesectors is called “slipping replacement”.

[0017] In case where there is no defective sector on the user area, datais written only on the user area, as shown in the upper layout of FIG.2. On the other hand, if there are defective sectors in the PDL, as manysectors in the spare area as defective sectors in the user area are usedfor sector replacement, as shown in the lower layout of FIG. 2.

[0018] A sector may become defective due to a deterioration in qualityby cyclic reproduction operation of the optical disc. Such a defectivesector is referred to as a “grown” defective one. Hence, when data iswritten to the optical disc, every sector which has not been listed inthe PDL is examined to determine if it has a grown defect. Each sectoridentified as defective one is subjected to the sector slippingalgorithm and the address of that sector is added to the PDL toguarantee that data is not written to the defective sector withoutsector verification process from the next write operation on.

[0019] In this way, the number of entries in the PDL increases as thewrite operation is repeated.

[0020] The criterion by which a sector is identified as bad one is asfollows. A sector with ECC (hereinafter referred to as “ECC sector”) isconstructed by data of 182 bytes×13 rows, as shown in FIG. 5, and a PID(physical identification) is assigned uniquely to each sector. The PIDis written on each sector at four reserved locations. The sector isdetermined as defective sector if there are three or more errors in thePID read-out in one sector or if the number of rows having four or moreerror bytes in one sector is one or more. ECC block is classified as badone when the number of rows having four or more error bytes in one ECCblock is six or more.

[0021] SDL Creation and Management (in Reproduction Operation)

[0022] When the optical disc is placed into service, sectors on the discmay become defective. Hence, while reproducing the optical disc, sectorswhich have not been listed in the PDL are examined to determine whetheror not they became grown defective sectors. If one sector is determinedas bad one, data recorded in 16 logical sectors of the ECC block havingthe bad sector (bad ECC block) is transferred to a valid ECC block whichis available on the spare area sequentially, as shown in FIG. 3. Thisscheme is called “linear replacement”. Then, a pair of the physicaladdress of the first or head sector of the defective ECC block and thephysical address of the first sector of the replacement ECC block isstored as an entry of the SDL.

[0023] When there is a lack of usable spare blocks in a present group,full flag corresponding to the group in the SDL is set to 1 and validspare blocks are borrowed for linear replacement from the spare area ofanother group.

[0024] In reproduction operation, each ECC block is determined as badone if the number of rows having four or more error bytes in one ECCblock is eight or more or if there are one or more sectors in which morethan three PID read-out arise.

[0025] When data is written to or read out from a DVD-RAM, a logicalblock address which is sent from the associated host computer to aDVD-PAM drive is translated to a physical target address. The PDL isthen reviewed to determine if any slip adjustment is needed. That is,the physical target address is compared to those of defective sectors inthe PDL. If it is determined that the sector at the physical targetaddress is defective, the defective sector is skipped and the subsequentsectors are examined until a valid sector is found. Then the physicaltarget address is adjusted so as to locate the next valid sector. Inreproduction operation, the physical target address is compared to thelist of the SDL to check if any sector replacement is required. If thephysical target address is matched with one of those in the SDL, thephysical target address of the replacement sector is read out from theSDL.

[0026] In case of optical disc which is dedicated to moving pictures orspeech, it is crucial that the audio/video data is reproduced inreal-time. However, the reproduction operation is interrupted for ashort period of time corresponding to the sector replacement requiringdata movement on the optical disc when grown defective sectors whichhave not been listed in the SDL are detected during reproduction. Inthis case, the reproduction speed of data recorded on the defectivesectors is lowered, resulting in a short interruption of reproduction ofaudio/video data.

[0027] No management of new defective areas which have not been listedin the PDL and SDL at the reproduction time can be a method for solvingthe short interruption by the linear replacement. In this case, however,when the already-written audio/video data is erased and then anewaudio/video data is overwritten to the VDR, the new data may be writtento the defective sectors or blocks. As a result; read-out error ofaudio/video data which is newly recorded on such defective sectors orbocks cannot be avoid.

SUMMARY OF THE INVENTION

[0028] It is therefore a primary object of the present invention toprovide a method for creating defect management information whichenables to reproduce audio/video data on an information recording mediumin real-time regardless of the presence of defective sectors and toavoid writing data to the defective sectors when new audio/video data isrecorded to the recording medium, and to provide an apparatus and anoptical disc for realizing the method.

[0029] To achieve the object, the present invention provides a methodfor creating defect management information of an information recordingmedium comprising the steps of detecting the presence of defective areason an information recording medium on the basis of read-out errors ofaudio/video data reproduced from the information recording medium; andwriting location information of the detected defective areas at areserved area on the information recording medium, which can be situatedadjacent to or separated from a general defect management informationarea of the information recording medium.

[0030] The method for creating defect management information accordingto the present invention further comprises the step of moving thelocation information of the detected defective sectors recorded in thereserved area into the general defect management information area, whenone of pre-assigned operations such as erasing operation is requested.

[0031] An apparatus for creating defect management information of aninformation recording medium according to the present inventioncomprises a means for storing the location information of the detecteddefective areas separately according to whether or not the data to bereproduced is audio/video data or not; and a means for writing the twosets of location information of the detected defective areas intorespective reserved areas on the information recording medium.

[0032] The apparatus for creating defect management informationaccording to the present invention further comprises a means forobtaining addresses of the area in which data to be erased is recorded;a means for reviewing the storing means keeping the locationinformation, or addresses of audio/video data's detective areas anddetermining whether or not there is any defective area, address of whichis matched with the obtained addresses; and a means for moving thematched addresses between the areas for defect information.

[0033] An information recording medium according to the presentinvention: comprises a first area for storing location information ofdefective areas to avoid writing data to the defective areas on theinformation recording medium; and a second area for storing informationsignifying, location information of the defective areas in whichaudio/video data is recorded, the second area being arranged so that itis close to or separated from the first area.

[0034] According to the present invention, while reproducing data fromthe information recording medium, it is checked whether or not there areerrors in the read-out of the data being reproduced. In case whereread-out errors are detected during reproduction of audio/video data,location information of the corresponding defective areas is stored in areserved area on the optical recording medium without sector replacementor stored in a portion of the storing means temporarily. The reservedarea for the location information may be located close to or separatedfrom the reserved area for general defect management information.

[0035] After that, if erasing of data on the information recordingmedium is requested, the address obtaining means obtains addressinformation of the area in which the data to be erased is recorded.Next, the location information, or addresses of defective areas whichare temporarily stored in the storing means are read out and are thencompared with the obtained addresses to determine if there are matchedaddresses. The, general defect, management information is renewed toinclude the matched addresses by the moving means.

[0036] According to the present invention, it is possible to reproduceaudio/video data in real-time regardless of the presence of defectivesectors by eliminating reproduction delay which arises due toreplacement of defective areas on the information recording medium, andto prohibit data from being written to the defective areas which aredetected during reproduction, when new data is written to the,information recording medium.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are included to provide afurther understanding of the invention, illustrate the preferredembodiment of this invention, and together with the description, serveto explain the principles of the present invention.

[0038] In the drawings:

[0039]FIG. 1 is a layout figure showing the partition of rewritable areaof an optical disc and defect lists;

[0040]FIG. 2 is a drawing explaining slipping replacement algorithm inthe write operation;

[0041]FIG. 3 is a drawing explaining linear replacement algorithm in thereproduction operation;

[0042]FIG. 4 is a block diagram showing a preferred embodiment ofoptical disc recording/reproducing apparatus of the present invention;

[0043]FIG. 5 shows a layout of an sector attached with ECC;

[0044]FIG. 6 is a flowchart showing the write process to the opticaldisc;

[0045]FIG. 7 is a flowchart showing the reproduction process ofaudio/video (A/V) data from the optical disc according to the method ofcreating defect management information of the present invention;

[0046]FIG. 8 is a flowchart showing the reproduction process of non-A/Vdata from the optical disc;

[0047]FIG. 9 is a flowchart showing the defective list updating processwhen A/V data is erased; and

[0048]FIG. 10 is a layout figure showing the rewritable area of theoptical disc according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0049] The preferred embodiment of the present invention will bedescribed below in detail referring to the accompanying drawings.

[0050]FIG. 4 depicts a partial block diagram of a VDR player embodyingthe creation method of defective management information according to thepresent invention. The VDR player comprises an optical pickup 10 forreading/writing data from/to an optical disc; a servo controller 110 forcontrolling the optical pickup 10; a read-out signal processing unit 40for classifying the type of data reproduced from the optical disc; a PIDdetector 50 for detecting the PID of data which is read out from thedisc; a SDL manager 90 for judging whether a sector is defective or notbased on read-out error of the detected PID, and for selecting newdefective sectors which have not been listed in the SDL by using defectinformation in the SDL; a reproducing unit 60 for decompressing andprocessing A/V data received from the read-out signal processing unit40; an interface RAM 130 for temporarily storing the A/V datatransferred to a host computer; a T-PDL (Temporary PDL) manager 80 forjudging whether a sector is defective or not on the basis of read-outerror of the A/V data and for selecting new defective sectors which havenot been listed in the T-PDL; memory 70 for temporarily storing the PDL,SDL, and T-PDL; an address manager 120 for obtaining the physicaladdresses of sectors on which data to be erased are recorded, whenerasing process of data is requested; a write signal processing unit 30for moving information on the physical addresses which are matched withthose stored in the T-PDL to the PDL on the optical disc; and laser beamcontroller 20 for controlling laser for writing data to the opticaldisc;

[0051] With reference to flowcharts of FIG. 6 or FIG. 9, and FIG. 4, themethod for creating defective management information of an optical discaccording to the present invention will be described below in detail.

[0052] Once the optical disc drive starts to reproduce the optical disc,the PDL and the SDL are read from the lead-in area of the optical discand are then stored in a PDL-section memory 70 a and a SDL-sectionmemory 70 c, respectively. Defective sectors stored in the PDL areskipped, and instead of bad sectors kept in the SDL, data is read outand reproduced from the corresponding replacement sectors

[0053] Meanwhile, data which is read out from the optical disc by theoptical pickup 10 is inputted to the read-out signal processing unit 40,where a classification is made as to whether the data is A/V data ornot. Non-A/V data or control data is supplied to the SDL manager 90through the PID detector 50. A decision is made as to whether thenon-A/V data has read-out errors by the SDL manager. If it is determinedthat the non-A/V data has errors, an ECC block containing the sector(s)in which the non-A/V data is recorded is replaced by a replacement ECCblock on spare area. The non-A/V data is then recorded therein. A pairof the PID of the first sector of the defective ECC block and, PID ofthe first sector of the replacement ECC block are stored in theSDL-section memory 70 c.

[0054] On the other hand, if A/V data is reproduced, the A/V data istransferred to the host computer through the reproducing unit 60 and theinterface RAM 130. It is determined by the T-PDL manager 80 whether ornot the A/V data has read-out errors in the unit of sector. The PIDs ofsectors which are determined as defective are stored in the T-PDLsection memory 70 b.

[0055] In this way, The PIDs of defective-sectors where A/D data isrecorded are stored in the T-PDL section memory 70 b, and the PIDs ofdefective sectors of non-A/V data are stored in the SDL-section

[0056] memory 70 c. After reproduction operation is completed, defectinformation that has been added to the T-PDL section memory and theSDL-section memory is written to respective reserved areas on theoptical disc, as shown in FIG. 10. After that, when the disc isreproduced again, while defective sectors stored in the PDL and SDL areskipped, the defective sectors kept in the T-PDL are reproduced, notskipped. As a result, A/V data is reproduced in real-time without anysector replacement even if sectors containing the A/V data has beenidentified as defective ones.

[0057] When a user requests to erase data on the optical disc to recordnew data, a signal notifying erasing operation is sent to the opticaldisc drive. Once the signal is received, the PDL, SDL, T-PDL are allread out from the disc and are then stored in their respective memorysections 70 a, 70 c, 70 b. The PIDs of sectors containing the data to beerased are compared to those of defective sectors stored in the T-PDLsection memory 70 b. If there are matched PIDs, the matched PIDs aremoved from the T-PDL section memory 70 b into the PDL-section memory 70a through a bus line (not shown). As a result, the defective sectors areallowed to be slipped at the time of rewriting operation and the data isprohibited from being written to the defective sectors associated withthe matched PIDS. After the rewriting operation is completed, therenewed PDL is written to its reserved area on the optical disc.

[0058] On the other hand, in this embodiment of the present invention,it is possible that defective sectors in which non-A/V data is recordedmay not be replaced by replacement sectors but its PID may be stored inthe T-PDL section memory 70 b, like defective sectors where A/V data isrecorded.

[0059] The write operation according to the method for creatingdefective management information of the present invention is describedbelow in detail with reference to FIG. 6, which is the same as that ofthe prior art method.

[0060] If a write command is inputted to the optical disc drive (S10),it is, first, checked whether or not the write operation is completed(S13). Then, the PDL stored in memory 70 a is reviewed to determine ifthe physical address of the target sector is included in the PDL (S15).

[0061] If it is determined that the physical target address is includedin the PDL, the target sector is skipped and then the next target sectoris determined (S17). For the next target sector, the process from thestep S13 is repeated. On the other hand, in case where it is determinedin the step S15 that the target address is not included in the PDL, thetarget sector is examined to determine if the target sector has becomedefective since the last renewal of the PDL. That is, after reading outand decoding four PIDs recorded in that sector, it is checked whether ornot there are three or more errors in the read-out of PID (S19).

[0062] When three or more errors in the PID read-out are detected, thecorresponding sector is classified as defective one and the writeoperation is stopped. Next, the physical address of the defective sectornewly detected is added to the PDL on the optical disc by using thewrite signal processing unit 30 and the laser beam controller 20. Thenext target address is determined (S17) and the process from the stepS13 is repeated.

[0063] In case where the number of errors in the PID read-out in thetarget sector is less than three, that sector is considered asnon-defective one. Thus, the data is written to the valid sector and thenext target address is determined (S21). During the repetition of theabove steps, the write operation is terminated if it is determined inthe step of S13 that recording of all data is completed.

[0064] For write operation, regardless of whether or not the data to berecorded is A/V data or non-A/V data, slipping replacement is performedby referring to the PDL.

[0065] The reproduction operation according to the method for creatingdefective management information of the present invention is describedbelow in detail with reference to FIGS. 7 and 8.

[0066] If a reproduction command is inputted to the optical disc drive(S40), the read-out signal processing unit 40 determines whether thedata being reproduced is A/V data or non-A/V data by decoding data readout from the optical pickup 10 (S41), and outputs the data to either thePID detector 50 or the reproducing unit 60, depending on the data type.

[0067] In the case of non-A/V data, perfect reproduction is a moreimportant factor than reproduction continuity without slight delay. Itis, therefore, preferred that defective sectors corresponding to thenon-A/V data are subjected to the linear replacement algorithm, as inthe prior art method, which will be described below in detail.

[0068] After it is checked whether or not the reproduction is completed(S71), data is read out and reproduced from the target sector (S73). Atthis time, it is checked by the PID detector 50 whether or not there areone or more sectors having three or more errors in the PID read-out(hereinafter referred to as PID-error sector) in an ECC block (S75).

[0069] In case where there are one or more PID-error sectors in an ECCblock, the SDL manager 90 determines the ECC block containing thePID-error sector(s) as a defective block. The defective ECC block isreplaced by a non-defective replacement ECC block in the space area bythe linear replacement process and then the corresponding data isrecorded therein. At this time, information showing the replacement ofthe defective ECC block with a replacement ECC block is stored in theSDL-section memory 70 c. Then, the next target sector is determined andlocated (S77).

[0070] Even when there is no PID-error sector, the ECC block is examinedto check if there are new grown defects in the ECC block. The ECC blockis regarded as a bad ECC block if the number of rows having four or moreerror bytes in one 182-type row is eight or more in one ECC block (S79).The bad ECC block is replaced by an replacement ECC block through thestep of S77.

[0071] If the ECC block is determined as valid ECC block in the step ofS79, the data which is recorded on the ECC block is reproduced and thenext target sector is determined (S81). The reproduction operation isended if it is determined in the step of S71 that there is no more datato be reproduced.

[0072] On the other hand, when it is determined in the step of S41 thatthe data being reproduced is A/V data, reproduction method according tothe present invention which is different from the prior art method iscarried out, which will be described below in detail with reference toflowchart of FIG. 7.

[0073] First, it is checked whether or not reproduction operation iscompleted (S43), If not completed, data is read out and reproduced fromthe target sector (S45). At this time, it is checked by the PID detector50 whether or not there are two or more errors in the PID read-out inthe target sector (S47). If there are two or more PID read-out errors,the T-PDL manager 80 regards the target sector as bad one and stores theaddress of that sector in the T-PDL section memory 70 b. Next, the nexttarget address is determined and the optical pickup is moved to the nexttarget sector (S49)

[0074] Even when the number of errors in the PID read-out is less thantwo, whether the target sector is bad or not is examined by checking ifthe number of rows having four or more error bytes is four or more inone sector (S51). The sectors determined as bad ones are stored in theT-PDL memory section 70 b, as well. Next, the next target sector isdetermined. (S49).

[0075] If the target sector is classified as valid one in the step ofS51, just the next target sector is determined and the optical pickup ismoved to that target sector (S53). Finally, the reproduction operationis ended if it is determined in the step of S43 that there is no moreA/V data to be reproduced.

[0076] In short, if sectors where non-A/V data is recorded are judged asbad ones, the sectors are replaced with valid sectors on the spare area,so that the non-A/V data are reproduced without read-out error from thenext reproduction. On the other hand, in case of sectors where A/V datais recorded, when the sectors are determined as bad ones, no sectorreplacement is carried out to enable real-time reproduction. Instead,the addresses of the bad sectors are kept in a reserved area on theoptical disc which is separated from the reserved area for the PDL andSDL.

[0077] If A/V data on the optical disc is reproduced repeatedly, theT-PDL section memory 70 b comes to store the addresses of bad sectorswhich are newly detected during reproduction operation. Such informationon new bad sectors is written to a reserved area for the PDL on theoptical disc when an er ase command is issued by a user, which will beexplained below with reference to flowchart of FIG. 9 if an erasecommand is inputted to the optical disc drive (S101), the physicaladdresses of sectors in which the data to be erased is recorded areobtained by the address manager 120 (S107). Next, the physical addressesstored in the T-PDL section memory 70 b are read out (S109) and then theaddresses obtained by the address manager 120 are compared with those ofbad sectors in the T-PDL section memory (S111). If there is no matchedaddress, the erasing process is made (S115). If there are at least onematched addresses, the matched addresses stored in the T-L sectionmemory 70 b are moved into the PDL-section memory 70 a through the busline (S113) and then the erasing process is made (S115).

[0078] As shown in FIG. 10, a reserved location on the optical disc forthe T-PDL can be arranged such that it lies in the data area, separatedfrom the PDL and SDL, or in DMA of the lead-in area tog ether with thePDL and SDL. The former arrangement has an advantage of preserving theexisting defect management information area for the PDL and SDL. In thisarrangement, it is preferred that the space for the T-PDL is reserved ata location before or behind the area for storing a program menuinformation, which is accessed repeatedly in writing or reproductionoperation. In the latter arrangement, the order in which three defectlists lies in the DMA can be changed.

[0079] The bad sectors, addresses of which are moved from the T-PDLsection memory 70 b to the PDL-section memory 70 a, are slipped by theslipping replacement algorithm when new data is rewritten to the opticaldisc after erasing operation is completed. As a result, data isprohibited from being written to the bad sectors.

[0080] The foregoing is provided only for the purpose of illustrationand explanation of the preferred embodiments of the present invention,so changes, variations and modifications may be made without departingfrom the spirit and scope of the invention.

What is claimed is:
 1. A method for creating and writing defectmanagement information of an information recording medium, comprisingthe steps of: (a) detecting the presence of defective area in aninformation recording medium based on data reproduced from theinformation recording medium; (b) determining whether to move the dataon the detected defective area into a, replacement area; and (c)creating and writing the information signifying whether the replacementof the detected defective area is made or not.
 2. A method according toclaim 1, wherein said step (a) comprises the steps of: detecting thenumber of errors in the read-out of physical location information, whichis recorded several times repeatedly for every prescribed area on theinformation recording medium, and/or the number of error bytes in onerow which is produced from the encoding of each ECC; and determining thepresence of defective area in the information recording medium bycomparing the detected number of errors with a pre-specified referencenumber of errors.
 3. A method according to claim 1, wherein said step(b) determines the movement of the data recorded in the detecteddefective area into the replacement area based on whether or not thedata on the defective area is real-time data.
 4. A method according toclaim 1, wherein said step. (c) writes the location information of thedetected defective area to other information area which is separatedfrom a pre-specified defect management information area.
 5. A methodaccording to claim 4, further comprising the step of: updating thedefect management information in said pre-specified area by moving saidlocation information of the defective area in said other informationarea into said pre-specified defect management information area, whenerasing of data recorded in the area containing the defective area isrequested.
 6. A method for creating and writing defect managementinformation of an information recording medium, comprising the steps of:(a) detecting the presence of defective area in an information recordingmedium based on data reproduced from the information recording medium;and (b) determining whether to move the data recorded on the detecteddefective area into a replacement area based on type of the data.
 7. Amethod according to claim 6, wherein the data type in said step (b) isclassified by whether or not the data is real-time data.
 8. A methodaccording to claim 6, further comprising the step of: creating andwriting the information signifying whether the replacement of thedetected defective area is made or not.
 9. A method according to claim8, wherein said creating/writing step writes the location information ofthe detected area to other information area which is separated from apre-specified defect management information area.
 10. A method accordingto claim 9, further comprising the step of: updating said pre-specifieddefect management information by moving said location information on thedefective area in said other information area into said pre-specifieddefect management information area, when erasing of data recorded in thearea containing the defective area is requested.
 11. An informationrecording medium, comprising of: a first area for storing defectmanagement information which is used for controlling the replacement ofa defective area with a replacement area; and a second area for storingthe information signifying that the replacement of the defective area isbased on the type of the data recorded on the defective area.
 12. Aninformation recording medium according to claim 11, wherein said firstarea and said second area are located in either lead-in area or lead-outarea.
 13. An apparatus for creating and writing defect managementinformation of an information recording medium, comprising: a means fordetecting the presence of defective area in an information recordingmedium based on data reproduced from the information recording medium; ameans for determining whether to move the data on the detected defectivearea into a replacement area; and a means for creating and writing theinformation signifying whether the replacement of the detected defectivearea is made or not.
 14. An apparatus according to claim 13, whereinsaid detecting means comprises: a means for detecting the number oferrors in the read-out of physical location information, which isrecorded several times repeatedly for every prescribed area on theinformation recording medium and/or the number of error bytes in one rowwhich is produced from the encoding of each ECC; and a means fordetermining the presence of defective area in the information recordingmedium by comparing the detected number of errors with a pre-specifiedreference number of errors.
 15. An apparatus according to claim 13,wherein said determining means determines the movement of the datarecorded in the detected defective area into the replacement area basedon whether or not the data on the detective area is real-time data. 16.An apparatus according to claim 13, wherein said creating/writing meanswrites the location information of the detected defective area to otherinformation area which is separated from a pre-specified defectmanagement information area.
 17. An apparatus according to claim 16,further comprising a means for updating the defect managementinformation in said pre-specified area by moving said locationinformation on the defective area in said other information area intosaid pre-specified defect management information area, when erasing ofdata recorded in the area containing the defective area is requested.18. An apparatus creating and writing defect management information ofan information recording medium, comprising: a means for detecting thepresence of defective area in an information recording medium based ondata reproduced from the information recording medium; and a means fordetermining whether to move the data recorded on the detected defectivearea into a replacement area based on the type of the data.
 19. Anapparatus according to claim 18, wherein the data type is classified bywhether or not the data is real-time data.
 20. An apparatus according toclaim 18, further comprising: a means for creating and writing theinformation signifying whether the replacement of the detected defectivearea is made or not.
 21. An apparatus according to claim 20, whereinsaid creating/writing means writes the location information of thedetected defective area to other information area which is separatedfrom a pre-specified defect management information area.
 22. Anapparatus according to claim 21, further comprising a means for updatingsaid pre-specified defect management information by moving said locationinformation on the defective area in said other information area intosaid pre-specified defect management information area, when erasing ofdata recorded in the area containing the defective area is requested.